Now that you’ve set up the built-in users, you need to decide how you want to
manage all the other users.

The Elastic Stack authenticates users to ensure that they are valid. The
authentication process is handled by realms. You can use one or more built-in
realms, such as the native, file, LDAP, PKI, Active Directory, SAML, or Kerberos
realms. Alternatively, you can create your own custom realms. In this tutorial,
we’ll use a native realm.

In general, you configure realms by adding xpack.security.authc.realms
settings in the elasticsearch.yml file. However, the native realm is available
by default when no other realms are configured. Therefore, you don’t need to do
any extra configuration steps in this tutorial. You can jump straight to
creating users!